RESULTS 



Solid-Phase Amphipod Tests. Results of the amphipod test performed with Ampelisca abdita are 

 summarized in Table 6. Tests were performed in a series of 10 batches. The results of the tests of the 

 Central Long Island Sound control sediments are listed first, followed by mean survival data for each 

 station and site. Mean percent survival in the LIS sediments ranged from 83.2% to 99.0%. Normally, 

 an acceptable survival rate in control sediments is 85% or greater. The mean percent survival in the 

 controls in test series 3 and 6 were 83.2% and 85.0%, respectively. In both series, there was no pattern 

 of unusually low survival in tests of the Hudson-Raritan Estuary samples; therefore, the data were 

 accepted and re-testing was not conducted. Furthermore, in series 3 amphipod survival in the test 

 samples was either very high or very low; therefore, the relatively low survival in the controls probably 

 had no effect upon the tests of significance. However, in series 6 amphipod survival approximated 

 80% in several samples and the tests of significance may have been affected by the results of the tests 

 of the controls. 



The sediments from 54 of the 117 stations (46%) were significantly toxic (i.e., different from controls) 

 in the amphipod tests. A total of 16 of the 39 sites (41%) was significantly toxic in this test. Mean 

 percent survival ranged from 0.0 to 99.0% among the 117 stations. Mean percent survival in most of 

 the 117 samples ranged from 80 to 99%, but a considerable number (48) of the test results were in the 

 range of to 79% survival. Among all 117 samples, 0.0% survival was observed in three samples (9- 

 B, 10-A, and 18-C) and 0.1-10.0% survival was observed in five samples (9-A, 9-C, 12-A, 18-C, and 

 34-B). 



Based upon considerable previous experience with this test, differences in amphipod survival between 

 controls and test samples of 20% or more are significantly different in approximately 90% of the cases. 

 Also, the 20% or greater difference from controls was used by EMAP (Schimmel et al., 1994) as a 

 critical value in the interpretation of amphipod bioassay data. Therefore, stations and sites in which 

 mean amphipod survival was equal to or less than 80% of the controls are identified with two asterisks 

 in Table 6. 



Of the 43 samples in which amphipod survival was 80% or less of controls, 42 (98%) were signifi- 

 cantly different from the controls. Mean amphipod survival in 10 sites was 80% or less of controls and 

 significantly different from controls. There is a lower probability that test results in which mean sur- 

 vival was greater than 80% of the controls were actually significantly different from controls. There- 

 fore, in some samples with relatively high amphipod survival (>80%) the results of the t-tests, alone, 

 may over estimate the incidence of toxicity in these tests. 



Sediments from Zone F, Newark Bay/Arthur Kill/Kill van Kull, were most toxic (Table 6). All nine 

 stations and all three sites were significantly toxic to amphipods in this zone. Also, zones C and D, 

 upper East River and lower East River, respectively, were highly toxic. In the upper East River area, all 

 nine stations and two of the three sites were toxic. In the lower East River, abd eight of nine stations 

 were toxic. Sediments from zones B (western Long Island Sound), I (Central Raritan Bay), and K 

 (southern Raritan Bay) were least toxic; none of the stations was toxic in these zones. Sediments from 

 Zone A, lower Hudson River, were relatively low in toxicity. Some of the sediments in Zone M in New 

 York Bight were toxic, especially those from site 39 in the southern portion of this zone. 



Several spatial patterns in toxicity were apparent, based upon the data from this test (Figures 6, 7). 

 First, toxicity was very high in the upper East River and rapidly decreased eastward out into western 



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